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  • 1
    Keywords: Electronic books.
    Type of Medium: Online Resource
    Pages: 1 online resource (352 pages)
    Edition: 1st ed.
    ISBN: 9780128118436
    Series Statement: Issn Series
    DDC: 551.0285
    Language: English
    Note: Front Cover -- Advantages and Pitfalls of Pattern Recognition -- Advantages and Pitfalls of Pattern Recognition -- Copyright -- Contents -- Preface -- Acknowledgments -- I - From data to methods -- 1 - Patterns, objects, and features -- 1.1 Objects and patterns -- 1.2 Features -- 1.2.1 Types -- 1.2.2 Feature vectors -- 1.2.3 Feature extraction -- 1.2.3.1 Delineating segments -- 1.2.3.2 Delineating regions -- 1.2.4 Transformations -- 1.2.4.1 Karhunen-Loève transformation (Principal Component Analysis) -- 1.2.4.2 Independent Component Analysis -- 1.2.4.3 Fourier transform -- 1.2.4.4 Short-time Fourier transform and spectrograms -- 1.2.4.5 Discrete wavelet transforms -- 1.2.5 Standardization, normalization, and other preprocessing steps -- 1.2.5.1 Comments -- 1.2.5.2 Outlier removal -- 1.2.5.3 Missing data -- 1.2.6 Curse of dimensionality -- 1.2.7 Feature selection -- Appendix 1 Basic notions on statistics -- A1.1 Statistical parameters of an ensemble -- A1.2 Distinction of ensembles -- 2 - Supervised learning -- 2.1 Introduction -- 2.2 Discriminant analysis -- 2.2.1 Test ban treaty-some history -- 2.2.2 The MS-mb criterion for nuclear test identification -- 2.2.3 Linear Discriminant Analysis -- 2.3 The linear perceptron -- 2.4 Solving the XOR problem: classification using multilayer perceptrons (MLPs) -- 2.4.1 Nonlinear perceptrons -- 2.5 Support vector machines (SVMs) -- 2.5.1 Linear SVM -- 2.5.2 Nonlinear SVM, kernels -- 2.6 Hidden Markov Models (HMMs)/sequential data -- 2.6.1 Background-from patterns and classes to sequences and processes -- 2.6.2 The three problems of HMMs -- 2.6.3 Including prior knowledge/model dimensions and topology -- 2.6.4 Extension to conditional random fields -- 2.7 Bayesian networks -- Appendix 2 -- Appendix 2.1 Fisher's linear discriminant analysis -- Appendix 2.2 The perceptron -- Backpropagation. , Appendix 2.3 SVM optimization of the margins -- Appendix 2.4. Hidden Markov models -- Appendix 2.4.1. Evaluation -- Appendix 2.4.2. Decoding-the Viterbi algorithm -- Appendix 2.4.3. Training-the expectation-maximization /Baum-Welch algorithm -- 3 - Unsupervised learning -- 3.1 Introduction -- 3.1.1 Metrics of (dis)similarity -- 3.1.2 Clustering -- 3.1.2.1 Partitioning clustering -- 3.1.2.1.1 Fuzzy clustering -- 3.1.2.2 Hierarchical clustering -- 3.1.2.3 Density-based clustering -- 3.2 Self-Organizing Maps -- 3.2.1 Training of an SOM -- Appendix 3 -- Appendix 3.1. Analysis of variance (ANOVA) -- Appendix 3.2 Minimum distance property for the determinant criterion -- Appendix 3.3. SOM quality -- Topological error -- Designing the map -- II - Example applications -- 4 - Applications of supervised learning -- 4.1 Introduction -- 4.2 Classification of seismic waveforms recorded on volcanoes -- 4.2.1 Signal classification of explosion quakes at Stromboli -- 4.2.2 Cross-validation issues -- 4.3 Infrasound classification -- 4.3.1 Infrasound monitoring at Mt Etna-classification with SVM -- 4.4 SVM classification of rocks -- 4.5 Inversion with MLP -- 4.5.1 Identification of parameters governing seismic waveforms -- 4.5.2 Integrated inversion of geophysical data -- 4.6 MLP in regression and interpolation -- 4.7 Regression with SVM -- 4.7.1 Background -- 4.7.2 Brief considerations on pros and cons of SVM and MLP in regression problems -- 4.8 Classification by hidden Markov models and dynamic Bayesian networks: application to seismic waveforms of tectonic, volcani ... -- 4.8.1 Background -- 4.8.2 Signals related to volcanic and tectonic activity -- 4.8.3 Classification of icequake and nonterrestrial seismic waveforms as base for further research -HMM -- 4.8.3.1 Icequakes -- 4.8.3.2 Moon quakes. , 4.8.3.3 Classification of seismic waveforms using dynamic Bayesian networks -- 4.9 Natural hazard analyses-HMMs and BNs -- 4.9.1 Estimating volcanic unrest -- 4.9.2 Reasoning under uncertainty-tsunami early warning tasks -- Appendix 4.1. Normalization issues -- Appendix 4.2. SVM Regression -- Appendix 4.3. Bias-Variance Trade-off in Curve Fitting -- 5 - Applications with unsupervised learning -- 5.1 Introduction -- 5.2 Cluster analysis of volcanic tremor data -- 5.3 Density based clustering -- 5.4 Climate zones -- 5.5 Monitoring spectral characteristics of seismic signals and volcano alert -- 5.6 Directional features -- Appendix 5 -- Appendix 5.1 Davies-Bouldin index -- Appendix 5.2 Dunn index -- Appendix 5.3 Silhouette index -- Appendix 5.4 Gap index -- Appendix 5.5 Variation of information -- III - A posteriori analysis -- 6 - A posteriori analyses-advantages and pitfalls of pattern recognition techniques -- 6.1 Introduction -- 6.2 Testing issues -- 6.3 Measuring error -- 6.4 Targets -- 6.5 Objects -- 6.6 Features and metrics -- 6.7 Concluding remarks -- 6.7.1 Multilayer perceptrons -- 6.7.2 Support Vector Machines -- 6.7.3 MLP and SVM in regression analysis -- 6.7.4 Hidden Markov models and Bayesian networks -- 6.7.5 Supervised and unsupervised learning -- 7 - Software manuals -- 7.1 Example scripts related to Chapter 2 -- 7.1.1 Linear discrimination, principal components, and marginal distributions -- 7.1.2 The perceptron -- 7.1.3 Support Vector Machines -- 7.1.4 HMM example routines (from Theodoridis et al., 2010, see http://booksite.elsevier.com/9780123744869) -- 7.2 Example scripts and programs related to Chapter 3 (unsupervised learning) -- 7.2.1 K-means clustering -- 7.2.2 Mixed models -- 7.2.3 Expectation maximization clusters -- 7.2.4 Fuzzy clustering -- 7.2.5 Hierarchical clustering -- 7.2.6 Density-based clustering. , 7.2.7 Unsupervised learning toolbox: KKAnalysis -- 7.2.7.1 Preliminaries -- 7.2.7.2 Installation -- 7.2.7.3 Files -- 7.2.7.3.1 Input files -- 7.2.7.3.2 Output files -- 7.2.7.4 Getting started -- 7.2.7.4.1 The "Input File" frame -- 7.2.7.4.2 The "figures" frame -- 7.2.7.5 Configuring KKAnalysis-the "settings" -- 7.3 Programs related to applications (Chapter 4) -- 7.3.1 Back propagation neural network (BPNN) -- 7.3.2 SVM library -- 7.4 Miscellaneous -- 7.4.1 DMGA-generating ground deformation, magnetic and gravity data -- 7.4.2 Treating fault plane solution data -- Bibliography -- Bibliography -- Index -- A -- B -- C -- D -- E -- F -- G -- H -- I -- J -- K -- L -- M -- N -- O -- P -- Q -- R -- S -- T -- U -- V -- W -- X -- Back Cover.
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  • 2
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Journal of the American Chemical Society 83 (1961), S. 3724-3725 
    ISSN: 1520-5126
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Pure and applied geophysics 147 (1996), S. 57-82 
    ISSN: 1420-9136
    Keywords: Volcanic tremor ; cluster analysis ; Stromboli volcanoes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences , Physics
    Notes: Abstract The features of seismic activity on Stromboli are discussed and compared in terms of their relationship with the main changes of volcanic activity from 1990 to 1993. We considered a statistical approach for our data analysis. Cluster analysis was used to seek out classes of spectra which might characterize the condition of the volcanic system. The classes we have found provide insights into a scenario which evolves through different phases of volcanic activity, from paroxysms to low activity. We show that episodes of lava effusion and lava fountaining are heralded by variations in the spectral features of tremor after a preparation time. This result highlights the importance of tremor, and reveals that long-term observations are key to examine slow modifications in a volcanic system such as Stromboli, characterized by open conduits, and persistent explosive activity.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 1432-2013
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Zusammenfassung Im Anschluß an eine frühere Mitteilung (1954) wird über die Schwelle der Frequenzunterscheidung zweier nacheinander abwechselnd dargebotener rhythmischer Lichtblitzserien und über die Genauigkeit der Einstellung auf gleiche Frequenz berichtet. Die Unterschiedsschwellen und die mittleren Abweichungen sind bei der Festfrequenz 10 L/s (Lichtblitze/sec) kleiner als bei den Festfrequenzen 5 L/s und 16,7 L/s, die Einstellung erfolgt also bei 10 L/s am genauesten. Dies gilt auch für die Einstellung auf Frequenzgleichheit. Die Helligkeit des Flimmerlichtes hat in dem untersuchten Leuchtdichtenbereich von 5–170 asb keinen Einfluß auf die Unterschiedsschwelle, die Einstellung auf Frequenzgleichheit und die Standardabweichung. In der Unterschiedsschwelle, in der Einstellung auf Frequenzgleichheit und in der mittleren Abweichung besteht kein Unterschied zwischen rotem, gelbem, grünem, blauem und weißem Flimmerlicht. Gegenfarbigkeit von Fest- und Fragefrequenz beeinträchtigt die Einstellung auf Frequenzgleichheit nicht. Der Befund von Bartley, daß die subjektive Flimmerfrequenz einer Lichtblitzserie um so niedriger zu sein scheint, je heller das Flimmerlicht ist, läßt sich zur heterochromen Photometrie benutzen: Fest- und Fragefrequenz, die sich in ihrer Farbe unterscheiden, werden nur dann auf physikalisch gleiche Frequenz eingestellt, wenn beide gleich hell erscheinen. In der Unterschiedsschwelle, in der Einstellung auf Frequenzgleichheit und in der Standardabweichung besteht bei geübten Versuchspersonen kein Unterschied zwischen monokularem und binokularem Beobachten.
    Type of Medium: Electronic Resource
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  • 5
    Publication Date: 2016-05-04
    Description: Analytical Chemistry DOI: 10.1021/acs.analchem.6b00460
    Print ISSN: 0003-2700
    Electronic ISSN: 1520-6882
    Topics: Chemistry and Pharmacology
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  • 6
    Publication Date: 2021-01-18
    Description: The study of the kinematics and stress field related to seismicity makes an important contribution to the understanding of tectonic processes. In this kind of analysis, a crucial issue is identifying seismically homogeneous areas, which implies data classification and cluster creation. We present an approach that combines unsupervised learning techniques in order to reveal patterns in the focal mechanisms data set. In particular, a combination of two popular clustering algorithms, that is, self-organizing maps and Fuzzy C-means, was applied to focal mechanisms of events located in the Central Mediterranean region, characterized by a complex geodynamic framework. The analysis allowed identifying eight groups of focal mechanisms and their spatial distribution in the crust, and revealing the tectonic style of key sectors of southern Italy and of the neighboring offshore areas. A compressive regime was found between the lower Tyrrhenian Sea and southeastern Sicily, whereas extension prevails along the Calabrian Arc and the southern Apennines. A NW-SE transcurrent faulting between the Aeolian Islands and the Ionian Sea forms a transfer zone between these two domains.
    Description: Published
    Description: e2020JB020519
    Description: 4T. Sismicità dell'Italia
    Description: JCR Journal
    Keywords: Focal Mechanisms ; Central Mediterranean Area ; Tectonophysics
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 7
    Publication Date: 2021-02-02
    Description: We present a set of revised ground motion models (GMMs) for shallow events at Mt. Etna volcano. The recent occurrence of damaging events, in particular two of the strongest earthquakes ever instrumentally recorded in the area, has required revising previous GMMs as these failed to match the observations made for events with local magnitude ML 〉4.3, above all for sites situated close to the epicenter. The dataset now includes 49 seismic events, with a total of 1600 time histories recorded at distances of up to 100 km, and ML ranging from 3.0 and 4.8. The model gives estimates of peak ground acceleration (PGA, both horizontal and vertical), peak ground velocity (PGV, both horizontal and vertical) and 5%-damped horizontal pseudoacceleration response spectral ordinates (PSA) up to a period of 4 s. GMMs were developed by using the functional form proposed by Boore and Atkinson (2008). Furthermore, with a slightly modified approach, we also considered a regression model using a pseudo-depth (h) depending on magnitude according to the scaling law by Azzaro et al . (2017). Both models were applied to hypocentral distance ranges of up to 60 km, and up to 100 km, respectively. From the statistical analysis, we found that reducing the maximum distance from the event up to 60 km and introducing a magnitude-dependent pseudo-depth, improved the model in terms of total error. We compared our results to those derived with the GMMs for shallow events at Mt. Etna found by Tusa and Langer (2016) and for volcanic areas by Lanzano and Luzi (2019). The main differences are observed at short epicentral distances and for higher magnitude events. The use of variable pseudo-depth avoids sharp peaks of predicted ground motion parameters around the epicenter, preventing instabilities when using a GMM in probabilistic seismic hazard analysis.
    Description: Published
    Description: 2843–2861
    Description: 6T. Studi di pericolosità sismica e da maremoto
    Description: JCR Journal
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: article
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  • 8
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    Elsevier B.V.
    Publication Date: 2021-02-01
    Description: In supervised classification, we search criteria allowing us to decide whether a sample belongs to a certain class of patterns. The identification of such decision functions is based on examples where we know a priori to which class they belong. The distinction of seismic signals, produced from earthquakes and nuclear explosions, is a classical problem of discrimination using classification with supervision. We move on from observed data—signals originating from known earthquakes and nuclear tests—and search for criteria on how to assign a class to a signal of unknown origin. We begin with Principal Component Analysis (PCA) and Fisher's Linear Discriminant Analysis (FLDA), identifying a linear element separating groups at best. PCA, FLDA, and likelihood-based approaches make use of statistical properties of the groups. Considering only the number of misclassified samples as a cost, we may prefer alternatives, such as the Multilayer Perceptrons (MLPs). The Support Vector Machines (SVMs) use a modified cost function, combining the criterion of the minimum number of misclassified samples with a request of separating the hulls of the groups with a margin as wide as possible. Both SVMs and MLPs overcome the limits of linear discrimination. A famous example for the advantages of the two techniques is the eXclusive OR (XOR) problem, where we wish to form classes of objects having the same parity—even, e.g., (0,0), (1,1) or odd, e.g., (0,1), (1,0). MLPs and SVMs offer effective methods for the identification of nonlinear decision functions, allowing us to resolve classification problems of any complexity provided the data set used during earning is sufficiently large. In Hidden Markov Models (HMMs), we consider observations where their meaning depends on their context. Observations form a causal chain generated by a hidden process. In Bayesian Networks (BNs) we represent conditional (in)dependencies between a set of random variables by a graphical model. In both HMMs and BNs, we aim at identifying models and parameters that explain observations with a highest possible degree of probability.
    Description: Published
    Description: 33-85
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Keywords: pattern recognition ; supervised learning ; Support Vector Machines ; Multilayer Perceptrons ; Hidden Markov Models ; Bayesian Networks ; 04.04. Geology ; 04.06. Seismology ; 04.07. Tectonophysics ; 04.08. Volcanology ; 05.04. Instrumentation and techniques of general interest
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 9
    Publication Date: 2021-02-01
    Description: Patterns and objects are described by a variety of characteristics, namely features and feature vectors. Features can be numerical, ordinal, and categorical. Patterns can be made up of a number of objects, such as in speech processing. In geophysics, numerical features are the most common ones and we focus on those. The choice of appropriate features requires a priori reasoning about the physical relation between patterns and features. We present strategies for feature identification and procedures suitable for pattern recognition. In time series analysis and image processing, the direct use of raw data is not feasible. Procedures of feature extraction, based on locally encountered characteristics of the data, are applied. Here we present the problem of delineating segments of interest in time series and textures in image processing. In transformations, we “translate” our raw data to a form suitable for learning. In Principal Component Analysis, we rotate the original features to a system of uncorrelated variables, limiting redundancy. Independent Component Analysis follows a similar strategy, transforming our data into variables independent of each other. Fourier transform and wavelet transform are based on the representation of the original data as a series of basis functions—sines and cosines or finite-length wavelets. Redundancy reduction is achieved considering the contributions of the single basis functions. Even though a large number of features help to solve a classification problem, feature vectors with high dimensions pose severe problems. Besides the computational burden, we encounter problems known under the term “curse of dimensionality.” The curse of dimensionality entails the necessity of feature selection and reduction, which includes a priori considerations as well as redundancy reduction. The significance of features may be evaluated with tests, such as Student’s t or Hotelling's T2, and, in more complex problems, with cross-validation methods.
    Description: Published
    Description: 3-13
    Description: 5T. Sismologia, geofisica e geologia per l'ingegneria sismica
    Keywords: pattern recognition ; objects ; features ; 04.04. Geology ; 04.06. Seismology ; 04.07. Tectonophysics ; 04.08. Volcanology ; 05.04. Instrumentation and techniques of general interest
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: book chapter
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  • 10
    Publication Date: 2020-10-13
    Description: Magma transfer in an open-conduit volcano is a complex process that is still open to debate and not entirely understood. For this reason, a multidisciplinary monitoring of active volcanoes is not only welcome, but also necessary for a correct comprehension of how volcanoes work. Mt. Etna is probably one of the best test sites for doing this, because of the large multidisciplinary monitoring network setup by the Osservatorio Etneo of Istituto Nazionale di Geofisica e Vulcanologia (INGV-OE), the high frequency of eruptions and the relatively easy access to most of its surface. We present new data on integrated monitoring of volcanic tremor, plume sulphur dioxide (SO2) flux and soil hydrogen (H2) and carbon dioxide (CO2) concentration from Mt. Etna. The RMS amplitude of volcanic tremor was measured by seismic stations at various distances from the summit craters, plume SO2 flux was measured from nine stations around the volcano and soil gases were measured in a station located in a low-temperature (T ∼ 85 °C) fumarole field on the upper north side of the volcano. During our monitoring period, we observed clear and marked anomalous changes in all parameters, with a nice temporal sequence that started with a soil CO2 and SO2 flux increase, followed a few days later by a soil H2 spike-like increase and finally with sharp spike-like increases in RMS amplitude (about 24 h after the onset of the anomaly in H2) at all seismic stations. After the initial spikes, all parameters returned more or less slowly to their background levels. Geochemical data, however, showed persistence of slight anomalous degassing for some more weeks, even in the apparent absence of RMS amplitude triggers. This suggests that the conditions of slight instability in the degassing magma column inside the volcano conduits lasted for a long period, probably until return to some sort of balance with the “normal” pressure conditions. The RMS amplitude increase accompanied the onset of strong Strombolian activity at the Northeast Crater, one of the four summit craters of Mt. Etna, which continued during the following period of moderate geochemical anomalies. This suggests a cause-effect relationship between the anomalies observed in all parameters and magma migration inside the central conduits of the volcano. Volcanic tremor is a well-established key parameter in the assessment of the probability of eruptive activity at Etna and it is actually used as a basis for a multistation system for detection of volcanic anomalies that has been developed by INGV-OE at Etna. Adding the information provided by our geochemical parameters gave us more solid support to this system, helping us understand better the mechanisms of magma migration inside of an active, open-conduit basaltic volcano.
    Description: Published
    Description: online (due to Covid pandemic)
    Description: 4V. Processi pre-eruttivi
    Keywords: integrated monitoring ; soil gases ; plume SO2 ; volcanic tremor ; magma transfer ; Etna ; 04.08. Volcanology
    Repository Name: Istituto Nazionale di Geofisica e Vulcanologia (INGV)
    Type: Oral presentation
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